SETD1A and cyst: We hypothesize that after the loss of SC integrity during mid-pachytene due to the depletion of Set1 or Ash2, the germline cyst cells by mid-to-late-prophase I are not competent anymore to reassemble the SC, even after the delayed accumulation of oocyte-fate determinants (e.g., Orb) and the condensation of the oocyte–chromatin into a karyosome.